定量雷射超音波系統應用於全域性機械材料參數檢測

A full-field mechanical property mapping with quantitative laser ultrasound visualization system

吳佳翰(Chia-Han Wu)

指導教授 ： 楊哲化

國立臺北科技大學/機電學院/機電科技研究所/博士(2013年)

摘要

本研究目標在於開發一套非破壞、高速、高準確及全域性檢測之定量雷射超音波掃描顯像系統，並結合全域性機械材料參數重建演算法，開發一套適用於全域性材料機械性質分析平台，針對待測物進行全面性機械材料參數檢測。另外為測試系統之穩定度，本研究將開發之系統應用於等向性材料、具厚度減薄之試片、鍍膜之試片及具溫度變化分佈之試片等進行量測，由系統穩定性研究結果顯示，全域性厚度檢測與雷射位移計掃描針對具厚度減薄之試片，其減薄厚度約為100~200 ?m，以及鍍膜之試片，其鍍膜厚度約為100~200 ?m結果相當吻合，且彈性係數及蒲松比量測亦相當穩定。則具溫度變化分佈之試片，藉由溫度上升，待測物之彈性係數下降之關係，本研究全域性溫度檢測與紅外線熱像儀檢測結果，溫差小於10oC。最後將量測之平台應用於熔射鎳鋁合金膜層之檢測，其研究結果顯示，大氣電漿熔射及高速火焰熔射之鎳鋁合金膜層製程中，當氣體流速越快時，其彈性係數隨之上升；其高速火焰熔射製程之膜層厚度增加時，膜層之彈性係數亦隨之上升，並由研究中得知膜層彈性係數及厚度關係可用雙曲正切函數(hyperbolic tangent)描述；且利用高速火焰熔射製程之膜層，其彈性係數高於利用大氣電漿熔射製程之膜層；且利用全域性機械材料參數檢測，熔射鎳鋁合金膜層之製程的不均勻性主要原因為厚度不均勻，並與熔射鎳鋁合金噴塗之路徑有關，量測結果顯示厚度不均勻性最高約為100 ?m左右。
藉由本研究針對全域性機械材料參數檢測技術的開發，其全域性機械材料參數量測可以藉由非破壞、高速且高精度量測獲得材料全域性定性及定量結果。對於待測物缺陷檢測及材料製程之機械材料參數檢測，將可提供全域性檢測之實質貢獻。

關鍵字

結構健康監測 ； 定量雷射超音波系統 ； 全域性機械材料參數重建演算法 ； 熔射鎳鋁合金膜層之檢測

並列摘要

This research employs a nondestructive, rapid, high accuracy and full-field material characterization platform which integrates quantitative laser ultrasound visualization system (QLUVS) with mechanical property mapping reconstruction algorithm. The QLUVS uses a pulsed laser generate acoustic waves with fast scanning mechanical to research two dimensional scanning goal and then detected with a piezoelectric longitudinal transducer. By utilizing QLUVS, the spatial and temporal information of guided wave can be obtained with further signal processing. The theoretical models including guided waves propagating along single-layered plate, two-layered plate, surface wave for single-layered system and for two-layered system and signal processing including 2D spatial data interpolation, window shifting and 2D fast Fourier transform (2D FFT) will be integrated into mechanical property mapping reconstruction algorithm.
Finally this research is developed a novel full-field material characterization platform consisting of QLUS and mechanical property mapping reconstruction algorithm for full-field mechanical property mapping purpose. Further the accuracy and performance of developed platform will be investigated for full-field young’s modulus, Poisson’s ratio and thickness homogeneity inspection including isotropic plate, plate with defect, two-layered system with coating and bulk with temperature treating case. After platform performance testing, it is also applied for material characteristic in manufacturing Ni-Al thermal sprayed coating manufacture process. By means of this platform, the relationship between full-field mechanical property and thermal sprayed Ni-Al coatings of various manufacture conditions.
Utilizing the development of the full-field mechanical property inspection technology, full-field mechanical property measured by non-destructive, high-speed and high-precision measurements can be obtained in qualitative and quantitative results.

並列關鍵字

Nondestructive inspection ； guided wave ； quantitative laser ultrasound visualization system (QLUVS) ； mechanical property mapping reconstruction algorithm ； thermal sprayed coating manufacture

參考文獻

1. M. J. Ehrlich and J. W. Wagner, "Transient Lamb wave velocity determining using holographic mapping of spatial features of propagating waves," Research in Nondestructive Evaluation, vol. 1, no. 3, 1989, pp. 151-166.

2. J. C. P. Mckeon and M. K. Hinders, "Lamb wave scattering from a through hole," Journal of Sound and Vibration, vol. 224, no. 5, 1999, pp. 843-862.

3. J. C. P. Mckeon and M. K. Hinders, "Parallel projection and crosshole Lamb wave contact scanning tomography," Journal of the Acoustical Society of America, vol. 106, no. 5, 1999, pp. 2568-2577.

4. E. V. Malyarenko and M. K. Hinders, "Fan beam and double crosshole Lamb wave tomography for mapping flaws in aging aircraft structures," Journal of the Acoustical Society of America, vol. 108, no. 4, 2000, pp. 1631-1639.

5. E. V. Malyarenko and M. K. Hinders, "Ultrasonic Lamb wave diffraction tomography," Ultrasonics, vol. 39, no. 4, 2001, pp. 269-281.